Tech Down On Valuation Concerns -- Tech Roundup

Shares of tech companies ticked down amid concerns about the sector's valuation.

"The parallels to 1999 keep becoming stronger," said Craig Birk, executive vice president of portfolio management at money manager Personal Capital, in a note to clients. "Things are nowhere near as extreme or frothy as they were then...However, we suggest investors be cautious when they start feeling 'it is different this time.'"

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Mr. Birk noted that 70% of the last 1000 point gain in the Nasdaq Composite were directly attributable to Facebook, Apple, Amazon.com and Google. "Tech stock prices are being driven by a combination of rapidly rising earnings and expanding valuations," Mr. Birk said.

Days after Advanced Micro Devices suggested its chips were largely unaffected by security issues found in a variety of processors, Intel's rival has felt repercussions. Microsoft said some customers found their AMD-powered computers were unusable after applying the latest security patches for the Windows operating system.